Abstract: A method for monitoring the efficiency of a catalyst includes providing an oxygen sensor between an engine and the catalyst to generate an output signal indicative of oxygen content. The output signal is sampled to provide a first value indicative of the oxygen content of untreated exhaust. The exhaust is allowed to flow through the catalyst to produce treated exhaust and then the treated exhaust is caused to flow back to the oxygen sensor. The output signal is again sampled to provide a second value indicative of the oxygen content of treated exhaust. The second value is compared to the first value to provide an indication of the efficiency of the catalyst.

Abstract: Apparatus and method for forming sheets, comprising a pair of drums moving a belt to define a path for curing the sheets. Uncured material, preferably polychloroprene, is put on the belt and squeezed between the drum and a roller to adjust the thickness of the layer. The drums rotate at a rate to permit the material to cure between the first and the second drum. Ovens cure the polychloroprene, which is removed at the second drum. The sheet has a thickness of from at least 0.004 inches to more than 0.25 inches. A plurality of sources supply material of at least two colors to form a sheet having stripes. Preferred sheets have an elongation to break of about 150% to about 1500%, a tensile strength of about 5 Mpa to about 50 Mpa and a modulus at 300% elongation of about 1 Mpa to about 10 Mpa.